Apparatus and method for recording and/or reproducing data on an information storage medium using padding information, and the information storage medium

ABSTRACT

An apparatus and method for recording and/or reproducing data on a disc are provided using padding information, and a corresponding information storage medium. The recording method includes recording a recording unit block in which invalid data is padded in part of the block and recording padding information indicating that the invalid data is included. According to the method, a disc drive becomes able to distinguish valid data from invalid data in an error correction block such that reliability of reproduction increases and stability of the system is improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 10/847,675 filed on May 18, 2004, currentlypending, and claims the priority of Korean Patent Application No.2003-33127, filed on May 23, 2003, in the Korean Intellectual PropertyOffice, the disclosures of which are incorporated herein in theirentirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and an apparatus for recordingand/or reproducing data in units of a predetermined size on aninformation storage medium, and the information storage medium.

2. Description of the Related Art

Recording and/or reproducing data on an information storage medium suchas an HD-DVD, CD, or DVD is performed in units of a predetermined size.The units are referred to as recording unit blocks or reproducing unitblocks. An example of a recording unit block or a reproducing unit blockis an error correction block for correcting errors occurring when datais recorded or reproduced.

Assuming that the size of an error correction block is 64Kbytes, whendata with a size of only 4Kbytes, which corresponds not to the entireblock but to part of the error correction block, is to be recorded, theremaining part (60Kbytes) is filled with invalid values.

If the disc drive reads out the error correction block in order toreproduce the valid data occupying only part of the block, and performserror correction, error correction of codewords containing themeaningful 4Kbyte data is possible, but error correction of codewordshaving the meaningless 60Kbyte data is impossible and as a result it isdetermined that error correction is impossible in the entire errorcorrection block. Since the disc drive cannot distinguish which part ofthe error correction block has valid data and which part is filled withinvalid data, error correction or reproduction should be reattempted, orelse the error correction block, despite the fact that it contains somevalid data, is finally treated as an error block.

SUMMARY OF THE INVENTION

An aspect of the present invention provides an apparatus and method forrecording and/or reproducing data, by which a disc drive is made to beable to distinguish between valid data and invalid data in an errorcorrection block such that reliability of reproduction increases andstability of the system can be guaranteed, and a correspondinginformation storage medium.

According to an aspect of the present invention, there is provided arecording method including recording a recording unit block whereinvalid data is padded in part of the block, and recording paddinginformation indicating that the invalid data is included.

In accordance with an aspect of the present invention, in the recordingof padding information, the padding information is recorded tocorrespond to at least one recording unit block, to correspond to atleast one reproducing unit block, or is recorded in the recording unitblock.

According to an aspect of the present invention, the recording ofpadding information includes recording information indicating whether ornot there is padded data in at least one recording unit block orreproducing unit block corresponding to the information, or recordinginformation indicating the location of padded data in at least onerecording unit block or reproducing unit block corresponding to theinformation, or recording information indicating the value of datapadded in at least one recording unit block or reproducing unit blockcorresponding to the information.

According to another aspect of the present invention, there is provideda reproducing method including reading out at least one recording unitblock wherein valid data is included in part of the block and invaliddata is padded in a remaining part of the block; and based on thepadding information, obtaining the valid data.

According to an aspect of the present invention, the recording unitblock is an error correction block.

According to an aspect of the present invention, obtaining the validdata includes reading out the padding information recorded to correspondto at least one reproducing unit block, from an information storagemedium, or reading out padding information recorded in the recordingunit block.

According to another aspect of the present invention, obtaining thevalid data includes determining from the padding information whether ornot there is data padded in at least one recording unit block orreproducing unit block corresponding to the padding information, and ifthere is padded data, obtaining valid data excluding the padded data, orfinding from the padding information the location of data padded in atleast one recording unit block or reproducing unit block correspondingto the padding information, and obtaining valid data excluding thepadded data, or finding from the padding information the value of datapadded in at least one recording unit block or reproducing unit blockcorresponding to the padding information, and obtaining valid dataexcluding the padded data.

According to another aspect of the present invention, there is provideda recording apparatus including a pickup unit which records data on adisc; and a control unit which controls the pickup unit to record datain a recording unit block where invalid data is padded in part of theblock, and to record padding information indicating that the invaliddata is included in the block.

According to another aspect of the present invention, there is provideda reproducing apparatus including a pickup unit which reads out at leastone recording unit block where valid data is included in part of theblock and invalid data is padded in a remaining part of the block; and acontrol unit which obtains the valid data based on the paddinginformation.

According to another aspect of the present invention, there is providedan information storage medium including a recording unit block wherevalid data is included in part of the block and invalid data is paddedin a remaining part of the block; and padding information indicatingthat the invalid data is included.

According to an aspect of he present invention, the padding informationis recorded to correspond to at least one recording unit block, tocorrespond to at least one reproducing unit block, or is recorded in therecording unit block.

According to an aspect of the present invention, the padding informationincludes information indicating whether or not there is data padded inat least one recording unit block or reproducing unit blockcorresponding to the padding information, or the padding informationfurther comprises at least one of information indicating the location ofthe padded data and information indicating the value of the padded data.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a block diagram of an apparatus according to the presentinvention;

FIG. 2 is a block diagram of a disc drive to which the apparatus of FIG.1 is applied;

FIGS. 3A through 3G are reference diagrams showing padding informationaccording to embodiments of the present invention;

FIG. 4 is a reference diagram for explaining implementation of thepresent invention;

FIG. 5 is a schematic representation of a conventional overall encodingprocess; and

FIG. 6 illustrates the conventional composition of a data sector fromtwo data frames.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiments of the presentinvention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below to explain the presentinvention by referring to the figures.

Referring to FIG. 1, an apparatus according to an embodiment of thepresent invention is capable of recording and/or reproducing data andcomprises a writing/reading unit 1 and a control unit 2. According tothe control of the control unit 2, the writing/reading unit 1 recordsdata on a disc 100, which is an information storage medium according toan embodiment of the present invention, and reads out data in order toreproduce recorded data. The control unit 2 controls therecording/reproducing unit 1 so that the writing/reading unit 1 recordsdata in predetermined recording unit blocks, or processes data read bythe writing/reading unit 1 and obtains valid data. Reproducing refers toobtaining valid data by performing error correction for the read data,and is performed in predetermined units. The units for performingreproduction are referred to as reproducing unit blocks. A reproducingunit block corresponds to at least one recording unit block.

In a data recording operation, when the control unit is recording dataof a size that cannot completely fill a recording unit block on the disc100, valid data is stored in part of the recording unit block andinvalid data is padded in the remaining part to make a recording unitblock of a predetermined size and then this unit block is recorded.Also, padding information indicating inclusion of invalid data isrecorded on the disc 100. In the embodiment shown in FIG. 1, the paddinginformation is recorded in a recording unit block. Padding informationis not limited to an indication that invalid data is included, butrefers to information enabling valid information to be distinguishedfrom invalid information. This will be explained in more detail later.

In a data reproducing operation, the writing/reading unit 1 reads outfrom the disc 100 at least one recording unit block in which valid datais included in part of the block and invalid data is padded in theremaining part of the block. The control unit 2 extracts only the validdata based on the padding information contained in the recording unitblocks and reproduces the valid data.

FIG. 2 is a block diagram of a disc drive to which the apparatus of FIG.1 is applied. Referring to FIG. 2, the disc drive comprises a pickup 10as a writing/reading unit 1. The disc 100 is placed on the pickup 10. Inaddition, the disc drive comprises a PC I/F 21, a DSP 22, an RF AMP 23,a servo 24, and a system controller 25 as a control unit 2. The systemcontroller 25 performs initialization required for recording data.

In the data recording operation, the PC I/F 21 receives a recordingcommand with data to be recorded from a host. The DSP 22 adds additionaldata such as a parity for error correction of the data received from thePC I/F 21 and performs error correction and checking (ECC) encoding togenerate an ECC block, which is an error correction block, and modulatesthe ECC block according to a predetermined method. Here, if data that issmaller than the size of the ECC block is to be recorded, invalid datais padded with the smaller data to make a complete ECC block. Paddinginformation may be added before or after performing the ECC encoding.The RF AMP 23 converts the data output from the DSP 22 into an RFsignal. The pickup 10 records the RF signal output from the RF AMP 23 onthe disc 100. The servo 24 receives a command required for servo controlfrom the system controller 25 and servo-controls the pickup 10.

In the data reproducing operation, the PC I/F 21 receives a reproductioncommand from a host (not shown). The system controller 25 performs theinitialization required for reproduction. The pickup 10 emits a laserbeam onto the disc 100, obtains an optical signal by receiving areflected beam from the disc 100, and outputs the optical signal. The RFAMP 23 converts the optical signal output from the pickup 10 into an RFsignal and provides modulated data obtained from the RF signal to theDSP 22 while providing a servo signal for control of the pickup obtainedfrom the RF signal to the servo 24. The DSP 22 demodulates the modulateddata, performs error correction and outputs the resulting data. In thecase of an ECC block in which valid data is recorded in only part of theECC block, only valid data is reproduced by referring to the paddinginformation.

Meanwhile, the servo 24 performs servo control of the pickup 10, byusing the servo signal received from the RF AMP 23 and a commandrequired for servo control received from the system controller 25. ThePC I/F 21 transfers the data received from the DSP 22 to the host.

FIGS. 3A through 3G are reference diagrams showing padding informationaccording to embodiments of the present invention.

FIG. 3A shows, padding information that is recorded in each recordingunit block. Thus, padding information corresponds to each recording unitblock. That is, padding information is recorded in each recording unitblock. The recording unit blocks are units for recording data andusually have a predetermined size.

As shown in FIG. 3B, recording unit blocks are grouped into groups ofpredetermined number of recording unit blocks and padding information isrecorded in each group. Thus, padding information corresponds to aplurality of recording unit blocks. That is, padding information isrecorded in each group of recording unit blocks.

As shown in FIG. 3C, padding information is recorded in every tworecording unit blocks.

As shown in FIG. 3D, padding information is recorded in each reproducingunit block. A reproducing unit block corresponds to at least onerecording unit block. Accordingly, padding information can be actuallyrecorded in or out of a recording unit block.

As shown in FIG. 3E, padding information reproducing unit blocks aregrouped into groups of a predetermined number of the reproducing unitblocks and padding information is recorded in each of the groups ofreproducing unit blocks.

As shown in FIG. 3F, padding information is recorded in every tworeproducing unit blocks.

As shown in FIG. 3G padding information comprises padding presenceinformation 350, padding location information 360, and a padding value370. Padding presence information 350 indicates whether or not there ispadded data. Padding location information 360 indicates the locations ofvalid data and invalid data in a recording unit block. The padding value370 indicates a padded value. If a padded value is determined inadvance, it is not necessary to record the padding value 370.

By virtue of the padding information, the disc drive of FIG. 2 is ableto extract valid data from a recording unit block. Particularly, whenthe recording unit block is an error correction block, although it isimpossible to correct an error in a codeword including only invaliddata, if it is possible to correct errors in codewords containing validdata, the errors in these codewords can be corrected such that validdata is extracted and transmitted to the host. When an entire recordingunit block is transmitted, a part corresponding to invalid informationis transmitted, with the part containing a padded value when data isrecorded, without change.

Referring to FIG. 2, based on the padding information having thestructure described above, the operation of the disc drive will now beexplained in more detail.

Since the amount of management information, which is generally recordedin a lead-in or lead-out area of the disc 100 to smoothly use the disc100, is less than the size of a recording unit block (e.g., 64Kbytes),the system controller 25 pads the remaining part with a predeterminedvalue such as 00h so that a recording unit block of a predetermined sizecan be formed and transferred to the pickup 10. Also, when data isrecorded according to a record command of the host, and when the size ofthe data to be recorded is not a multiple of a recording unit block, thesystem controller 25 receives the data transmitted from the host,divides the data to fit the size of the recording unit block, and thenrecords the data. As for the leftover part of a recording unit blockwhich is not filled with the data, the system controller 25 pads thatpart with a predetermined value such as 00h so that recording unitblocks of a predetermined size can be formed and transferred to thepickup 10. Accordingly, the location immediately before an area where00h is padded in the recording unit block is the last part of an areawhere valid data is recorded.

When part of a recording unit block is padded with a predetermined valuesuch as 00h, the system controller 25 records the padding informationtogether so that the presence of the padded invalid data and thelocations of valid data and invalid data in a recording unit block areindicated, and the value of invalid data (i.e., the padded value; forexample, if 00h is padded, 00h, or if ffh is padded, ffh) is recorded.Thus, the location where valid data exists in a recording unit blockindicates the location where valid data is recorded in the recordingunit block, and the location where invalid data, for example, 00h,exists indicates where the invalid data is recorded in the recordingunit block. Accordingly, the locations of valid data and invalid data inthe recording unit block indicate a location up to which valid data isrecorded and beyond which invalid data is recorded.

Specific examples of implementations of embodiments of the presentinvention will now be explained in detail.

<Recording of Padding Information>

“Data frame” is terminology used in U.S. Pat. No. 6,367,049 andindicates a 2Kbyte data block, and generally, a 2Kbyte sector. FIG. 5 isschematic representation of a conventional encoding process. Referringto FIG. 5, the ECC format comprises an ECC cluster 510 formed of 304long distance Reed-Solomon error correction codes, and a burst indicatorsubcode (BIS) cluster 516 formed of 24 burst indicator subcodes.

Referring to FIGS. 4 and 5, in the process of generating this BIScluster 516, it is possible to allocate a predetermined part of the“control data” of “logical address+control data” 502 to padding presenceinformation 350 and a padding value 370 for a sector unit which is 2Kbytes long, in order to implement an embodiment of the presentinvention. For padding presence information 350 (for example, ‘1’indicates the presence of padded data, while ‘0’ indicates that there isonly normal data), 1 bit is needed for one sector (“Data Frame”) that is2Kbytes long and accordingly 32 bits (4 bytes) are needed. For a paddingvalue 370, 1 byte is needed for each sector and accordingly 32 bytes areneeded. When a padding value 370 is selected among some predeterminedvalues, it is desirable, but not required, to record informationindicating the predetermined values. (For example, if there are twovalues, 00h and ffh, which can be padded in sector units, the paddingvalues can be identified only by one bit indicating “0” or “1”.)

In short, the 4 byte padding presence information is recorded in“control data” of “logical address+control data” 502, the 32 bytepadding value 370 is recorded in “control data” of “logicaladdress+control data” 502, and the information indicating the paddingvalue 370 is allocated to “control data” of “logical address+controldata” 502.

When the padding value 370 is decided as one predetermined value, onlypadding presence information 350 need be recorded. In this case, thepadding presence information 350 can be stored in “physical address” 504(16*9 bytes) as shown in FIG. 5. Assuming, for example, the recordingunit block has 16 “physical addresses” 504 corresponding to 16 physicalsectors, and therefore one “physical address” 504 can be 9 bytes, thenpadding presence information 350 corresponding to 2 data frames can berecorded in the recording unit block.

In short, the recording unit block illustrated in FIG. 5 has 32 “dataframes,” including data frames 0-31, and therefore padding presenceinformation 350 can be recorded in an N-th physical address (N=0, 1, 2,. . . , 15) among 16 “physical addresses” 504.

<Padding Information Recording Operation>

In the structure for recording data in an ECC format, in order to recorddata on the disc 100, user data is encoded with an error correction codeto make an “ECC cluster” 510, and also a “BIS cluster” 516 is generatedto make a recording unit block. In doing so, information indicatingwhether or not each “data frame” of “user data 32 frames” 500 (64Kbytes)in FIG. 5 is padded with a predetermined value is stored in part of“physical address” 504 (16*9 bytes) or “logical address+control data”502 (32*18 bytes).

A host can communicate data with a disc drive (not shown) in units ofsectors, where 1 sector is 2Kbytes. For example, if the host commandsthe disc drive to record 50 sectors, for the remaining 18 sectors, datacorresponding to 14 sectors are padded with a predetermined value suchas 00h by the disc drive itself. Since the disc drive knows that data ispadded, the disc drive includes and records padding presence information350 and a padding value 370, as padding information for each sector, in“logical address+control data” 502 (32*18 bytes) or “physical address”504 (16* 6 bytes), according to an embodiment of the present invention.

When the host makes data into recording unit blocks and then transmitsthem to the disc drive, the disc drive does not know whether or not datais padded. Accordingly, in this case, the host should inform the discdrive of this fact.

When the disc drive records management information on a disc in order tomanage the disc under the control of the disc drive itself, althoughthere is no record command from the host, the disc drive already knowsthe amount of data to be recorded and determines whether or not to padthe data. Accordingly, as described above, the disc drive can recordpadding presence information and a padding value together, as paddinginformation for each sector, on the disc.

<Padding Information Reproducing Operation>

FIG. 6 illustrates the conventional composition of a data sector fromtwo data frames. Referring to FIG. 6, when user data recorded on thedata area of the disc is reproduced in response to a reproductioncommand from the host, or when the disc drive reproduces data without areproduction command of the host in order to obtain disc managementinformation recorded in the lead-in or lead-out of the disc, data isread out in units of recording/reproducing unit blocks from the disc anderror correction is performed. In doing so, if data is recorded in anECC format as illustrated in FIGS. 5 and 6, error correction isperformed first on “BIS block” 514 obtained by de-interleaving an “ECCcluster” 510. The disc drive obtains padding presence information 350and a padding value 370 for each sector (2Kbytes) as padding informationstored in “logical address+control data” 502 (32*18 bytes) or “physicaladdress” 504 (16*9 bytes) obtained by performing error correction on the“BIS block” 514. If error correction of the “BIS block” 514 is finished,error correction is performed on an “LDC block” 508. The “data block”506, which is obtained before ECC encoding an “LDC block” 508, isobtained in the same manner except that “19 columns” in FIG. 6 ischanged into “304 columns.”

Since the disc drive already knows the padding presence information 350and the padding value 370 for each “data frame,” the disc drive candistinguish a codeword containing valid information on an “LDC block”508 from a codeword containing invalid information. At this time, evenwhen there is a codeword containing only invalid information (i.e., apadded data frame) and it is impossible to correct errors in thecodeword, if it is possible to correct errors in codewords containingvalid information, these errors are corrected. Then, if the reproducingoperation is performed in response to the reproduction command from thehost, the corrected valid information is transmitted to the host, and ifthe reproducing operation is performed automatically by the disc driveitself, the information is used as is.

Meanwhile, in a disc structure where a linking area is arranged betweenrecording unit blocks, the padding information described above can berecorded in the linking area, and when data is reproduced, can beutilized. In order to increase the reliability of data, it ispreferable, but not required, that padding information read out from thelinking area can also be error-corrected.

FIG. 4 is a reference diagram for explaining implementation of thepresent invention. Referring to FIG. 4, after a “BIS cluster” 514 isreproduced, the validity of data corresponding to each “data frame” isknown, and it is known that only the first two “data frames” containvalid information. FIG. 4 shows an “LDC block” 508 to be error-correctedin this case.

If errors in the 19 codewords corresponding to the first two “dataframes” in the “LDC Block” 508 can all be corrected, the errorcorrection system transmits data corresponding to the first two “dataframes”, irrespective of whether or not errors in codewordscorresponding to the invalid 30 data frames are corrected, and whennecessary, transmits the remaining 30 data frames as padding values whendata is recorded.

If the recording method suggested in the embodiment of the presentinvention is not applied at the time of recording data, the disc drivehaving the error correction system cannot know the situation shown inFIG. 4 at all. Accordingly, even though it is possible to correct errorsin the 19 codewords corresponding to the two “data frames”, if it isimpossible to correct an error in any of the remaining codewords, thedisc drive reads out data again from the disc and performs errorcorrection or discards the block as erroneous.

Meanwhile, in a reproduction-only disc, padding information according tothe present invention can be recorded when data is stored duringmanufacture of the disc such that data reproduction efficiency can beimproved.

According to the present invention as described above, a disc drivebecomes able to distinguish valid data and invalid data in an errorcorrection block such that reliability of reproduction increases andstability of the system can be guaranteed.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A method for transferring data with respect to an information storagemedium, the method comprising: recording a physical cluster on theinformation storage medium, wherein the physical cluster comprises anerror correction code cluster comprising a plurality of data frames inwhich valid and/or invalid data are recorded, and a burst indicatorsubcode cluster in which status information indicating whether thephysical cluster comprises invalid data is recorded on the informationstorage medium.
 2. A method for transferring data with respect to aninformation storage medium, the method comprising: reproducing aphysical cluster from the information storage medium, wherein thephysical cluster comprises an error correction code cluster comprising aplurality of data frames in which valid and/or invalid data arerecorded, and a burst indicator subcode cluster in which statusinformation indicating whether the physical cluster comprises invaliddata is recorded on the information storage medium.